Recently, people are discussing the introduction of the fourth generation cellular system (4G) to achieve an improvement on additional performance of wireless communication. Techniques such as coordinated multiple point (CoMP) transmission in 4G are gaining more attentions.
The coordinated multiple points transmission is a technique such that multiple base stations coordinates with each other to perform data communication with a communication terminal. More specifically, the coordinated multiple points transmission refers to a technique where multiple base station perform data communication with one communication terminal simultaneously. The technique can expand the coverage of high data rate communication, and effectively solve the problem of interference between cells caused by orthogonal frequency division multiplexing (OFDM).
In a wireless communication system of performing coordinated multiple points transmission, the wireless communication terminal acting as a user equipment is required to feed back to the coordinated base stations various information and parameters which can reflect the state of downlink channels and can help the base stations to determine the design of transmission schemes (a set of points involved in the coordinated multiple points transmission, the transmission scheme for the coordinated multiple point, modulation and coding scheme, and etc.). Such information and parameters will be collectively called as channel state information in the following. Currently, there are two schemes for feeding back multiple channel state information for the coordinated multiple points transmission. One is the mode where multiple channel state information are fed back via time division multiplexing (TDM). Another is the mode where multiple channel state information are fed back via other non-time division multiplexing such as frequency division multiplexing (FDM) or code division multiplex (CDM).
In the time division multiplexing scheme, multiple channel state information are transmitted over the same physical uplink control channel (PUCCH) or physical uplink shared channel (PUSCH) and reach the base station sides at different times. In the non-time division multiplexing scheme, multiple channel state information are transmitted by using the multiplexing mode such as Frequency Division Multiplexing or Code Division Multiplex and reach the base station sides at the same time.